SEROLOGICAL EVIDENCE OF HUMAN GRANULOCYTIC EHRLICHIOSIS IN SWITZERLAND

To investigate whether human granulocytic ehrlichiosis (HGE) is preval ent in Switzerland, 1515 human serum samples from individuals with dif ferent risks for tick exposure were tested for antibodies to Ehrlichia phagocytophila, a surrogate marker of the agent of HGE. The distribut ion of titres showed marked differences between sera of individuals wi th no or low risk for tick exposure and those with a high risk. The re sults of serological testing provided evidence of HGE in Switzerland a s well as evidence of two types of coinfections: those with the agent of HGE and Borrelia burgdorferi, and those with the agent of HGE and t he central European tickborne encephalitis virus.